Hey T., wanted to lend my support and share what works for me. I am a divorced mother of a 7 year old boy with ADHD, in second grade. My ex and I split when my son was 4 years old. I work full time and have my son 50% time. I pick him up two days a week from school after work (in the evening) and the other day I work from home. The first couple days feel hard - its late and we need to do dinner/homework/bath/bedtime. Here is what has helped:
1. no "screen time" (computer/movies/video games) on school nights. I've tried to set reasonable limits but it always ends in a fight. It was hard to draw the line at first, but now my son knows what to expect.
2. reading time happens while I make dinner. he has to read 20 minutes a night for homework, and this is the best time to do it. I get dinner done, he has a quiet moment to get settled and crosses something off his list.
3. other homework gets done right after dinner. I've found that after a meal he is more settled and can focus on the homework.
4. we have the same schedule every night. the nights where i have deviated there are arguments and upsets. its boring, but it REALLY helps.
5. in working out this schedule, i sat my son down and told him what we were doing. I listed all the reasons why we can't have screen time or go see friends in the evening. At seven years old, he is old enough to understand.
I would also echo what other moms have said about the divorce being new and perhaps trying counseling. I would argue against "getting control of your sons" - in my experience, once you push them, they will keep pushing back. I do recommend sitting down with your son to talk about what works. You'll be surprised at his observations.
Good luck! hope things get easier for you.